Prediction of the failure mode of automotive steels resistance spot welds

2020 ◽  
Vol 25 (6) ◽  
pp. 511-517
Author(s):  
Mohsen Sheikhi ◽  
Shaghayegh Jaderian ◽  
Yousef Mazaheri ◽  
Majid Pouranvari
Keyword(s):  
Failure Mode ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds

scholarly journals Effect of weld nugget size on failure mode and mechanical properties of microscale resistance spot welds on Ti–1Al–1Mn ultrathin foils

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878528 ◽  
Author(s):  
Feng Chen ◽  
Shiding Sun ◽  
Zhenwu Ma ◽  
GQ Tong ◽  
Xiang Huang
Keyword(s):  
Mechanical Properties ◽  
Failure Mode ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Weld Nugget ◽  
Interfacial Failure ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds ◽  
Pullout Failure

We use tensile–shear tests to investigate the failure modes of Ti–1Al–1Mn microscale resistance spot welds and to determine how the failure mode affects the microstructure, microhardness profile, and mechanical performance. Two different failure modes were revealed: interfacial failure mode and pullout failure mode. The welds that fail by pullout failure mode have much better mechanical properties than those that fail by interfacial failure mode. The results show that weld nugget size is also a principal factor that determines the failure mode of microscale resistance spot welds. A minimum weld nugget size exists above which all specimens fail by pullout failure mode. However, the critical weld nugget sizes calculated using the existing recommendations are not consistent with the present experimental results. We propose instead a modified model based on distortion energy theory to ensure pullout failure. Calculating the critical weld nugget size using this model provides results that are consistent with the experimental data to high accuracy.

Effect of weld nugget size on overload failure mode of resistance spot welds

2007 ◽  
Vol 12 (3) ◽  
pp. 217-225 ◽  
Author(s):  
M. Pouranvari ◽  
H. R. Asgari ◽  
S. M. Mosavizadch ◽  
P. H. Marashi ◽  
M. Goodarzi
Keyword(s):  
Failure Mode ◽  
Weld Nugget ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds

Influence of Paint Baking on the Energy Absorption and Failure Mode of Resistance Spot Welds in TRIP1180 Steel

2021 ◽  
Vol 143 (9) ◽  
Author(s):  
D. V. Marshall ◽  
D. Bhattacharya ◽  
J. G. Speer
Keyword(s):  
Energy Absorption ◽  
Failure Mode ◽  
Low Energy ◽  
Interfacial Failure ◽  
Spot Welds ◽  
Resistance Spot ◽  
Pull Out ◽  
Resistance Spot Welds ◽  
Tension Testing ◽  
Cross Tension

Abstract Resistance spot welds (RSWs) in advanced high strength steels frequently exhibit interfacial failure during cross-tension testing: a mode of fracture associated with low-energy absorption. Automotive assembly lines include a paint application and baking cycle after the vehicle assembly and joining processes to cure paint and any adhesives used for assembly. In this article, the effects of a typical baking cycle: 180 °C for 20 min, on the failure mode and energy absorption during cross-tension testing of RSWs made in a TRIP1180 steel are reported. Further, short-time baking cycles of 30 s, 90 s, and 4 min were employed to investigate how quickly these baking effects are activated. RSWs, which exhibited interfacial failure and a low-energy absorption of 30.9 J in the as-welded condition, saw a change in a failure mode to partial interfacial failure and a 260% increase in energy absorption after baking for 30 s. After baking for a longer time (4 min), welds failed by button pull-out and exhibited a 296% increase in energy absorption during cross-tension testing. Baking for the full 20 min resulted in no additional improvement than was observed in the 4 min condition. The mechanisms responsible for the majority of the improvement in weld performance during baking are found to be activated after only 30 s of baking.

On the Failure Mode of Resistance Spot Welded Hsla 420 Steel / Tryb Uszkodzenia Zgrzewanych Spoin Stali Hsla 420

2013 ◽  
Vol 58 (1) ◽  
pp. 67-72 ◽  
Author(s):  
M. Pouranvari
Keyword(s):  
Failure Mode ◽  
Fusion Zone ◽  
Peak Load ◽  
Spot Weld ◽  
Zone Size ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds ◽  
Resistance Spot Weld ◽  
Pullout Failure

Failure mode of resistance spot welds (interfacial vs. pullout) is a qualitative measure of resistance spot weld performance. Considering adverse effect of interfacial failure mode on the vehicle crashworthiness, process parameters should be adjusted so that the pullout failure mode is guaranteed ensuring reliability of spot welds during vehicle lifetime. In this paper, metallurgical and mechanical properties of HSLA 420 resistance spot welds are studied with particular attention to the failure mode. Results showed that the conventional weld size recommendation of 4t0:5 (t is sheet thickness) is not sufficient to guarantee pullout failure mode for HSLA steel spot welds during the tensile-shear test. Considering the failure mechanism of spot welds during the tensileshear test, minimum required fusion zone size to ensure the pullout failure mode was estimated using an analytical model. Fusion zone size proved to be the most important controlling factor for peak load and energy absorption of HSLA 420 resistance spot weld.

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